Island



(No Model.)

Rmmvs FRIGTION CLUTCH.

No. 467,652. Patented Jan. 26, 1892.

WITN E55 E5 Www 71 71ML PATENT OFFICE.,

ROBERT F. IIARGRAVES, OF PROVIDENCE, RHODE ISLAND.

FRICTION-CLUTCH.

SPECIFICATION forming part of Letters Patent No. 467,652, dated January26, 1892.

Application tiled May 22, 1891. Serial No. 393,778. (No model.)

To @ZZ 1071/0771. t may concern,.-

lle it known that I, ROBERT F. I'IARGRAVES, of the city and county ofProvidence, in the State of Rhode Island, have invented a certain newand useful Improvement in Friction-Clutches for Pulleys; and I declarethe following to be a specification thereof, reference being had to theaccompanying drawings.

Like letters indicate like parts.

Figure lis a side elevation of my invention when the friction-clutch andpulley are in engagement, the pulley, segments, and clutchlrub beingshown in vertical diametrical section. Fig. EZ is a rear elevation of myinvention, the sectional parts of said figure being o n line or m ofFig. l. Fig. 3 is a side' elevation showing the friction-clutch andpulley out of engagement with each other, the pulley being shown. invertical diametrical sect1on. Fig. l is a top plan of the parts as seenfrom lineyy of Fig. 3.

My invention consists of a sliding hub rotatable with the shaft, butmovable along it by means of a spline, and provided with fixed arms,which are diametrically opposite each other and which are inclinedoutwardly, a fixed hub upon said shaft and having pivotalIy-mountedlever-arms, which are slotted at both ends, the slots on one endreceiving the fixed arms of the sliding hub and the slots on the otherend receiving the pins or cross-pieces of the sliding bars of thefrictionclutch, and a supporting-plate whereon said clutch-bars aremovablaall arranged and operating substantially as hereinafterspecified.

In the drawings, A is the shaft, and a is a spline.

B B are collars secured to the shaft A by set-screws b b.

O is a sliding hub movable along the shaft, and rotatable with it bymeans of the spline a. The hub C has a circumferential groove c toreceive the shipping-lever (not shown) and also twodiametrically-opposite arms D, integral therewith or rigidly fastenedthereto, Which arms extend angularly toward the clutching mechanism, asseen in Figs. l and 3. The arms D are longitudinally grooved, as shownat d.

E is the clutchhub, which is fast upon the shaft A. It has the earpiecese, on which lever-arms F are mounted pivotally by the pins f. The outerends of the levers F are bent, enlarged, and slotted, as shown in Figs.l and 3, and the inner endsof said levers are also slotted, as seen insolid lines in Fig. l and in dotted lines in Fig. 2. Set-screws g at thebent ends ot'- the levers F project into the grooves d of the arms D.

G is a supporting-piece fixed upon the shaft A. Guides 7L are fastenedupon the support G by screws, as shown in Figs. 2 and 4. Thefriction-clutch members or segments II have two bars I each, on whichare the hubs 't'. A

pin j passes through the hubs t' and through the rear slot of the leverF. The bars I are movable on the support G, and are kept in slidingcontact therewith by the guides h. J is a pulley loosely mounted on theshaft A, and 7c is the hub of said pulley.

IVhen the parts are in the position shown in Fig. 3, the friction-clutchis disengaged from the pulley. The hub O lies snugly against the collarand the screws g project into the grooves d of each arm D, as seen insaid figure. Now by sliding the hub C on the spline and shaft toward thepulley the arms D are moved into the slots of the bent ends of thelevers F, the points of the screws g sli'de along the grooves CZ, and,by reason of the inclined surfaces of said arms and slots so engaged bythe grooves and screws, the outer or enlarged ends of the levers F aredrawn toward the shaft A and the inner ends of the levers are moved inan opposite direction. By the connection of the levers F by their slotson the inner ends with the pins or cross-pieces of the sliding bars Isaid bars, with their respective segments or clutch members II, aremovedoutwardly in directions diametrically opposite each other and thesegments are crowded into forcible contact with the inner surface of theflange or rim of the pulley J, thus holding the pulley in frictionalengagement with the clutch and co1npeiling said pulley to turn with it.The clutching position of the parts is illustrated in Fig. l. Todisconnect the clutch and pulley, the hub C is moved toward the collarB, and the arms D, sliding along the slots of the levers F, spread saidlevers apart at their outer ends, and thereby bring the inner ends ofsaid levers toward the shaft A. This move' IOO ment causes thebars I toslide inwardly and withdraws the segments or clutch members Il fromContact with the rim of the pulley J. As the arlns D and the slots ofthe bent ends ot' the levers F F are at an angle with the shaft A, asshown, it is evident that the arms, which project into and are engagedwith said slots, respectively, as described, exert the same degree ofpower to operate the levers F when the hub C is moved away from the hubE as when the hub C is moved toward the hub E.

In friction-clutches which have radially` movable shoes or brakes it hasbeen found that the centrifugal force developed by the rapid revolutionof the pulley causes said shoes or brakes to press with increased poweragainst the rim of the pulley. The releasing mechani-sm exerting itspower in a direction toward the shaft or center is not always suficientto counteract this centrifugal force, and so the shoe or brake hasatendency to cling to the rim and to continue to revolve with the pulleyfor an appreciable time. It is important that the engagement anddisengagement should be practically instantaneous. In my device thisresult is accomplished by slotting the bent end of each of the levers Fand inserting in said slots, respectively,the ends of theangularly-projecting arms D, as hereinbefore specified.

The screws g serve not only to keep the le vers F and arms D in the sameplane of motion by reason of the projection of said screws i into thegrooves d, but also to adjust the arms D and levers F to each other andto take up the wear.

I claim as a novel and useful invention and desire to secure by LettersPatentl. In a friction-clutch for pulleys, having radially-movableshoes, the combination,with a shaft and pulley, of a fixed support uponthe shaft, levers mounted pivotally on said support and having theirinner ends adapted to lnove said shoes radially and their outer endsbent and slotted, as shown, and a hub movable on said shaft and havingangularly projecting arms to enter the slotted ends of said levers,respectively, to operate the same, substantially as speciiied.

2. In a friction-clutch for pulleys, the combinatiomwith a shaftandpulley, of the hub E upon said shaft-and having the earfpieces c andsupporting-piece G, the sliding clutch member consisting of the segmentsI-I and bars I, said bars being movable in guides on saidsupportingpiece and provided with cross-pins, and the levers F,mountedon said ear-pieces e and having slots to engage with the cross-pins ofthe bars I, substantially as specified.

The combination of the shaft A, having the spline a, collar B,pulley J,the -fixed hub E, having the ear-pieces e, the support G, the guides h,the clutch members H, the sliding bars I, having the cross-pins j, thebent and slotted levers F, having the set-screws g, and the sliding hubC, having the grooved arms D, all arranged `and operating substantiallyas specified.

ROBERT F. HAR-GRAVES. lVitnesses:

EDWARD F. Lo'vEJov, WARREN R. PERCE.

